1. Field of the Invention
This application relates to a semiconductor memory having redundancy memory cells to relieve defects.
2. Description of Related Art
A semiconductor memory includes redundancy memory cells in order to relieve defects and improve yields. The semiconductor memory judges whether an address signal supplied together with an access request coincides with a defective address (a redundancy judgment) or not and if the address signal coincides with the defective address, the semiconductor memory accesses a redundancy memory cell instead of a real memory cell. Techniques related to memory redundancy are disclosed in Japanese Laid-open Patent Publication No. 2002-74943, Japanese Laid-open Patent Publication No. 2001-243764, and Japanese Laid-open Patent Publication No. 2003-68071.